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50 Cards in this Set
- Front
- Back
The most important functions of the kidneys are to regulate the ______and composition of the ____
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Volume, ECF (extra cellular fluid)
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T or F: Kidneys require a "torrential" amount of blood flow to allow glomerular filtration.
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True; Renal Blood Flow = 20% of resting CO
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Glomerular Filtration Rate (GFR) is regulated mainly by...
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balanced tone of afferent and efferent
arterioles. |
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Kidneys function by copious,
nonselective glomerular ________ and regulated tubular _________ of most of the filtrate. |
filtration, reabsorption
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Glomerular filtrate contains all small molecules in a similar concentration to plasma, but _____ are retained in the bloodstream.
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Proteins
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____ is the best measure of kidney function
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GFR (glomerular filtration rate)
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We use _______ as a marker for GFR
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creatinine
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As kidney function falls, serum creatinine ________
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increases
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Reabsorption of many solutes is
driven by... |
basal and lateral Na-K-ATPase linked to many co-and counter-transporters. (Note that the Na-K_ATPase is the main character.)
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ICF is rich in _______
ECF is rich in _______ (About 140 mEq/l each) |
ICF is rich in potassium
ECF is rich in sodium (About 140 mEq/l each) |
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Cell membranes are freely permeable to _____, which keeps the osmolality of the ICF and ECF equal.
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Water
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Plasma is rich in _______, while the interstitial fluid is opposite. _______ pressure from _______ keeps fluid in the circulation.
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albumin, oncotic, albumin
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ECF VOLUME is controlled by the balance of ____.
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Na
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ECF [Na] is controlled by _____ and ____.
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Thirst, ADH
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The entire renal cortex is _______ to plasma.
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isotonic
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Concentration/Dilution of urine is determined by the water-permeability of the _______ and ______ (via ADH).
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Distal Convoluted Tubule (DCT), Collecting Duct (CD)
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Potassium is mostly filtered in the _____ of the nephron, while most of the secretion takes place in the _____ of the nephron.
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Proximal convoluted tubule, Distal convoluted tubule
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Kidneys regulate plasma [K], [H+], [Ca], and a host of other concentrations, but will sacrifice all to the prime function of regulating ___ ______.
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ECF Volume
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General findings in GLOMERULAR disease
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Proteinuria, Edema, HTN, hematuria (not all have to be present)
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General findings in TUBULAR disease
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NO (or little) proteinuria, NO edema, low/normal BP, NO hematuria
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NEPHROTIC Syndrome
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Proteinuria***, edema, hypoalbuminemia, hypercholesterolemia (not all have to be present)
Hint: nephROtic = pROtein |
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NEPHRITIC Syndrome
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Hematuria***, HTN, Oliguria, Acute Renal Failure, Increased blood [K+]
Hint: Look for hematuria! |
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Acute Renal Failure: Onset and Prognosis
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Minutes to Days; Reversible
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Chronic Renal Failure: Onset and Prognosis
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Months to Years; damage "arrestable" but not reversible. If progressing to end-stage renal disease, prepare for dialysis and/or transplant.
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The junctional complexes between the epithelial cells become MORE _______ as you progress from the proximal convoluted tubule towards the collecting duct.
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tight (less permiable)
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Equation: Net filtration pressure
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Puf = (Pgc -Pbs) - ONCOTICgc
Note: "Oncotic" is a pi symbol. |
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Equation: Glomerular Filtration Rate
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GFR = (Kf)(Puf)
or GFR = ((Ucreatinine)(V)) / (Pcreatinine) Note: using the clearance equation of creatinine to estimate GFR will cause a slight overestimation because there is some secretion of creatinine into the filtrate. |
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Equation: Clearance
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Cx = (Ux x V)/Px
Cx = Clearance of substance x from the plasma, Ux = Concentration of substance x in the urine, V = Flow rate of urine Px = Concentration of substance x in the plasma. |
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Equation: Renal PLASMA Flow
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RPF = (Upah x V) / Ppah
Upah = Urine concentration of PAH Ppah = Plasma concentration of PAH Note: We use PAH because it's filtered but NOT reabsorbed/secreted. |
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Equation: Renal Blood Flow
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RBF = (ERPF)/(1.0 – Hematocrit)
ERPH = effective renal plasma flow, basically, renal plasma flow. |
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Equation: Filtration Fraction
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Filtration Fraction = GFR/RPF
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Equation: Filtered Load
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Filtered Load = GFR x plasma concentration
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Equation: Total Body Water (weight)
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60% of body weight
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Equation: Intercellular Fluid (weight)
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40% of body weight
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Equation: Extracellular Fluid (weight)
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20% of body weight
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Equation: Interstitial Fluid (weight)
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15% of body weight (part of the 20% of the body weight made up of extracellular fluid)
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Equation: Plasma (weight)
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5% of body weight (part of the 20% of the body weight made up of extracellular fluid)
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Major INTRACELLULAR cation
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Potassium
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Major EXTRACELLULAR cation
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Sodium
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Osmolality vs. Tonicity
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Osmolarity: Amount of solute per given volume of water
Tonicity: Amount of solute per given volume of water that CANNOT cross the membrane |
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ADH secretion will respond faster to changes in ________ rather than _______.
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osmolarity, volume
...more sensitive to osmolarity |
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T of F: Hyponatremia can occur in the setting of a normal/excess/deficient amount of total body sodium.
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TRUE, it can simply be due to whatever amount of sodium you have being too diluted/concentrated/etc...
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T or F: Hyponatremia can cause symptoms.
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TRUE, for example, once you get down towards 110mEq/L, then you could have seizures and slip into a coma.
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What is the important gauge you use to treat a hyponatremic patient - the sodium level itself (the measured value) or symptoms?
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SYMPTOMS - correct a normal-appearing patient's hyponatremia SLOWLY, and correct a seizing/symptomatic patient's RAPIDLY. (The rate sodium correction is proportional to the rate of Sx onset.)
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What is the irreversible brain injury caused by too rapid correction of hyponatremia?
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Central Pontine Myelinolysis
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As far as Effective Arterial Blood Volume is concerned (EABV), the biggest deal about cirrosis _________ of the splanchnic vasculature.
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Vasodilation
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Define and Equation: Fractional excretion of sodium
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The percentage of sodium actually excreted after being filtered out in the glomerulus:
(Urine [Na] / Plasma [Na]) / ((Urine [Creatinine]) / (Plasma [Creatinine])) * 100 |
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Fractional excretion of Na GREATER than 1% means you're in a sodium _____ state.
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losing
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Fractional excretion of Na LESS than 1% means you're in a sodium _____ state.
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retaining
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Treatment of edema (three steps in appropriate order)
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1 - Treat underlying disease
2 - Decrease sodium and water intake 3 - Increase excretion of Na and water (Diuretics, local compession (stockings), and bed rest) |